1. Field of the Invention
This invention generally relates to trimmers used for cutting grass and weeds by a rotating cutting line and more particularly to a strut assembly supporting the major mass of a line trimmer.
Hand held power operated vegetation trimmers driving the free end portion of a monofilament line in an angular direction about the axis of a spindle forming a continuation of a motor drive shaft are in general use for cutting weeds, edging lawns and mowing in areas inaccessible to mowers.
One brand of such line trimmers is presently marketed under the trademark WEEDEATER and is generally referred to as a string trimmer or line trimmer. These line trimmers are generally used in the manner intended, namely while a line is rotated or whipping in a generally horizontal plane about a generally vertical axis.
In general, conventional line trimmers feature a downwardly facing rotary head having a radially projecting arcuate shield having a down turned flange at its radially outer edge. The head is mounted on the vertical drive shaft of a motor in a motor housing supporting the shield and connected with a generally tubular shaft projecting angularly upward from the motor housing and terminating in a handle end. In some trimmers a second handle is added to the handle intermediate its ends for aid in supporting the mass of the motor and components.
The main problem in operating such a vegetation trimmer is that the user must support the mass of the device in cantilever fashion forwardly of his body and swing it in arcs back and forth during the trimming action. Many user's suffer muscle strain from the mass of the device and its vibration.
In many trimmers the line is advanced as it wears by manually bumping a hub, forming a part of the spindle head, against the ground to extend the line.
Further, another problem in using the device results in the inability of the user to blend the height of the trimmed grass with the height of the lawn mower cut grass which is partially, at least, due to the difficulty involved in physically controlling the trimmer, particularly, when the user is of small stature.
This invention eleviates most of the above problems by forming a strut which supports the majority of the mass of a trimmer while in use.
2. Description of the Prior Art
U.S. Pat. No. 4,891,931 issued Jan. 9, 1990 to Holland for WEED CUTTER WHEEL KIT discloses a pair of axle mounted wheels depending from a bracket secured to the angularly upward handle shaft of a whirling line weed trimmer, which permits forward and rearward movement of the weed trimmer about the supporting wheels.
U.S. Pat. No. 5,095,687 issued Mar. 17, 1992 to Andrew et al for ADJUSTABLE SUPPORT WHEEL ASSEMBLY FOR ROTATING FLEXIBLE LINE-TYPE VEGETATION TRIMMER discloses a caster wheel mounted on the depending end of a vertical shaft secured at its upper end, by a clip and clamp, to the angular upward shaft handle for supporting the mass of a weed trimmer. The depending end portion of the caster shaft is stabilized by connection with the line trimmer shield at its radially rearward portion.
U.S. Pat. No. 4,224,784 issued Sep. 30, 1980 to Hansen et al for ATTACHMENT FOR LINE TRIMMER and U.S. Pat. No. 4,829,755 issued May 16, 1989 to Nance for TRIMMER WHEELS are believed good examples of the further state-of-the-art. The Hansen patent features a pair of wheels secured to an angularly upward extending shaft handle for side ways movement of the line trimmer to support the latter in a vertical mode so that it may be used as an edge trimmer. The Nance patent features a pair of wheels connected with the control shaft of a line trimmer at the rearward limit of its line trimmer guard for forward and rearward movement of the line trimmer in line trimmer mass supporting relation.
The invention is distinctive over all of the above named patents by providing a compression spring interposed between telescoping members forming a strut for supporting the mass of a line trimmer and is secured to the angularly upwardly directed operating handle by a clamp and serrated joint pivot connection on the clamp. The lowermost telescoping member is provided with a hemiellipsoidal surface for gliding over soil, lawn and grass during the vegetation trimming action.